Pharmacokinetics of pefloxacin in pigs after single intramuscular application

D. Dimitrova, V. Katsarov, D. Tsoneva

Abstract. Investigation of the pharmacokinetics of pefloxacin and its metabolite norfloxacin after single intramuscular application of pefloxacin mesylate at 10 mg/kg in pigs. The study was performed on eight healthy pigs, about 60 days of age. Blood plasma pefloxacin and norfloxacin concentrations were determined by a validated HPLC assay with UV detection. The primary pharmacokinetic parameters of pefloxacin were calculated by the two-compartmental method, whereas those of norfloxacin – by the non-compartmental method. The pharmacokinetic parameters of pefloxacin (mean±SEM) were as followed: elimination half-life (t ) – 6.68 0.52 h, mean residence time (MRT) – 9.71 0.54 h, maximum plasma concentrations (C ) – 0.594±0.12 μg/ml, time to reach C (T ) – 1/2β max max max 1.14±0.03 h, area under the plasma concentration curve from hour 0 to hour 36 (AUC ) – 6.06±0.18 μg.h/ml. Combined effective plasma concentrations of 0-36 h pefloxacin plus norfloxacin over 0.259 μg/ml were detected until the 12th hour after injection, and levels over 0.06 μg/ml – until the 24th hour. Pefloxacin 5 % solution, applied intramuscularly to pigs at a dose of 10.0 mg/kg resulted in effective plasma antimicrobial concentrations against clinically important bacterial infections for 12–24 h.